Without the Byzantine Empire, there never would have been Western civilization.
Western civilization is generally regarded as the child of Athens, Jerusalem, and Rome. That is, in the West, our philosophical and political thought is derived from that of the ancient Greeks; our Christian religion comes from the Jewish religion, and both of these came to us via the Roman Empire and the civilization and culture it created.
Western society has other forefathers as well: we would be unwise to give the Byzantine Empire short shrift. The ways in which it has influenced our world for the good, and indeed, created the parameters of our society at its healthiest and strongest, are insufficiently appreciated today. In its confusion, uncertainty, and lack of direction, the West has lost its way. There is a great deal it can, and should, learn from Byzantium.